PAK1 and Parkinson disease: Most of the differentially regulated exosomal proteins in the WT background (e.g. ATP6V0C, VAMP3, LAMP1, CALR, RAB7A, TUBA4A, RAC1, PARK7, SNCA, CAMK2, PAK1, HSPA8, ARPC4, ACTR3, RAP2C, CTNNB1, MAPT, PPP3CA, GLUL, SLC6A1, SLC6A11), which are classified in the top regulated IPA pathways (Fig. 3B, C, Supplementary Table 4B), are altered in the same fashion as identified DEGs in PD patients pinpointed by transcriptomics meta-analysis studies [52].